Method of Providing a Mobility Service

1. A method comprising: running an application on user equipment having mobility service functionality; using the mobility service functionality of the user equipment to receive packets from a home agent of a mobility service, the mobility service allowing the user equipment to change point-of-attachment to the Internet without changing source IP address, the mobility service functionality allowing transparent network connection to the application; determining that the home agent of the mobility service has become unavailable; and in response to determining that the home agent of the mobility service has become unavailable, notifying the application of the need to change the source IP address and causing the application to obtain access to a network from the mobility service functionality, wherein the network is the last network that the mobility service functionality was managing prior to determining that the home agent of the mobility service has become unavailable or the best access available for the application.

2. The method as claimed in claim 1 , comprising periodically trying to reconnect to the home agent after determining that the home agent has become unavailable.

3. The method as claimed in claim 1 , comprising making a reconnection to the home agent, and in response to making a reconnection to the home agent, informing the application that mobility service is again available.

4. A non-transitory computer readable medium comprising program code adapted to perform the method of claim 1 when the program code is run on a processor.

5. A method comprising: running an application on user equipment having mobility service functionality for receiving packets from a home agent of a mobility service, wherein the mobility service allows the user equipment to change point-of-attachment to the Internet without changing source IP address, the mobility service functionality allows transparent network connection to the application, and the application is notified of the need to change the source IP address when the home agent of the mobility service has become unavailable; determining that the home agent of the mobility service has become unavailable; periodically trying to reconnect to the home agent after the determining that the home agent has become unavailable; reconnecting to the home agent when the home agent becomes available; and in response to making a reconnection to the home agent, informing the application that mobility service is again available.

6. The method as claimed in claim 5 , the method comprising causing the application to inherit a network from the mobility service functionality in response to determining that the home agent of the mobility service has become unavailable and notifying the application of the need to change the source IP address.

7. The method as claimed in claim 6 , wherein the network is a general packet radio service, GRPS, network or a wireless local area network, WLAN.

8. The method as claimed in claim 6 , wherein the network is the last network that the mobility service functionality was managing prior to determining that the home agent of the mobility service has become unavailable or the best access available for the application.

9. The method as claimed in claim 5 , further comprising receiving a signal from the application to resume mobility service functionality.

10. The method as claimed in claim 9 , wherein discontinuation or resuming of the mobility service causes a change in the source IP address.

11. A non-transitory computer readable medium comprising program code adapted to perform the method of claim 5 when the program code is run on a processor.

12. An apparatus for a user equipment, the apparatus being adapted to: run an application on the user equipment; provide mobility service functionality for receiving packets from a home agent of a mobility service and for allowing transparent network connection to the application, the mobility service allowing the user equipment to change point-of-attachment to the Internet without changing source IP address; determine that the home agent of the mobility service has become unavailable; and in response to determining that the home agent of the mobility service has become unavailable, notify the application of the need to change the source IP address and cause the application to obtain access to a network from the mobility service functionality, wherein the network is the last network that the mobility service functionality was managing prior to determining that the home agent of the mobility service has become unavailable or the best access available for the application.

13. The apparatus as claimed in claim 12 , wherein the network is a general packet radio service, GRPS, network or a wireless local area network, WLAN.

14. An apparatus for a user equipment, the apparatus being adapted to: run an application on user equipment; provide mobility service functionality for receiving packets from a home agent of a mobility service and for allowing transparent network connection to the application, the mobility service allowing the user equipment to change point-of-attachment to the Internet without changing source IP address; determine that the home agent of the mobility service has become unavailable and to notify the application of the need to change the source IP address in response thereto; periodically try to reconnect to the home agent after the determining that the home agent has become unavailable; reconnect to the home agent when the home agent becomes available; and in response to making a reconnection to the home agent, inform the application that mobility service is again available.

15. The apparatus as claimed in claim 14 , adapted further to cause the application to inherit a network from the mobility service functionality in response to determining that the home agent of the mobility service has become unavailable and notifying the application of the need to change the source IP address.

16. The apparatus as claimed in claim 14 , wherein the network is a general packet radio service, GRPS, network or a wireless local area network, WLAN.

17. The apparatus as claimed in claim 14 , wherein the network is the last network that the mobility service functionality was managing prior to determining that the home agent of the mobility service has become unavailable or the best access available for the application.